- β-lactamase enzymes mediate bacterial resistance by hydrolyzing the β-lactam ring of β-lactam antibiotics, which is essential for their antibacterial activity.
- This hydrolysis inactivates the antibiotic, preventing it from binding to penicillin-binding proteins (PBPs) and disrupting cell wall synthesis.
- Without an intact β-lactam ring, the antibiotic cannot exert its bactericidal effect, leading to resistance.
- This mechanism is the primary way many bacteria evade β-lactam antibiotic action.

Reference: Katzung, Basic & Clinical Pharmacology, 14th Edition, Chapter 48